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Biomedical subjects

A Dominguez

Publications and source records attributed to A Dominguez.

At least 55 records · Page 3Linked to original sources
PubMed1990

Successful zidovudine therapy for HIV-related severe thrombocytopenia. Report of a sustained remission.

Five patients, two homosexuals and three drug abusers, with HIV-related severe thrombocytopenia, four of whom had also bleeding episodes, experienced a full remission of thrombocytopenia after 1,200 mg/day zidovudine treatment. None of the patients had acquired immunodeficiency syndrome (AIDS) or AIDS-related complex. Platelet counts began an upward trend at the end of the 3rd week and reached values higher than 140 x 10(9)/l towards the end of the 8th week of treatment. Patient's platelets remained stable after more than 4 months of active treatment. This is the first report of zidovudine-induced long-term remission of HIV-associated severe thrombocytopenia.

Acute Disease↗
PubMed1990

Fatal poisoning by Rumex crispus (curled dock): pathological findings and application of scanning electron microscopy.

A case of fatal poisoning due to ingestion of the plant Rumex crispus (curled dock) is described. The patient, a 53-year-old male, presented with gastrointestinal symptoms, severe hypocalcemia, metabolic acidosis and acute hepatic insufficiency. Despite therapeutic measures, the patient died 72 h after ingestion of the plant material. Noteworthy among the pathological findings were centrolobular hepatic necrosis and birefringent crystals in the liver and kidneys that were identified by histochemical techniques and scanning electron microscopy. These observations are compared with other reports in the medical literature, with an emphasis on the risk involved in the use of these plants for culinary or medicinal purposes.

Edema↗
PubMed1989

Sporulation of several species of Streptomyces in submerged cultures after nutritional downshift.

Streptomyces griseus ATCC 10137, S. griseus IMRU 3570, S. griseus JI 2212, S. acrimycini JI 2236 and S. albus G sporulated abundantly in several liquid media after nutritional downshift. Spores formed in submerged cultures were viable and as thermoresistant as aerial spores. Scanning electron microscopy showed that submerged spores are morphologically similar to aerial spores. The sporulation of the Streptomyces strains tested in complex medium appeared to be triggered by phosphate nutritional downshift, induced by addition of Ca2+ to the medium. Spore-shaped bodies were formed by S. lividans JI 1326 and S. coelicolor JI 2280 when grown in complex medium supplemented with Ca2+ and proline. The thermoresistance of these spore-shaped bodies differed from that of aerial spores.

Calcium Chloride↗
PubMed1982

Autonomic neuropathy in the skin: a histological study of the sympathetic nerve fibres in diabetic anhidrosis.

In diabetics with the anhidrotic syndrome, autonomic nerve fibres were studied in skin biopsies using argentic techniques and light microscopy. The Minor test was used to differentiate normal from anhidrotic skin areas. In the anhidrotic areas, histology of the nerve fibres showed beading, spindle-shaped thickening and fragmentation adjacent to the sweat glands. These changes were similar to those observed in two patients who had previously undergone lumbar sympathectomy. No abnormalities of the sympathetic nerve endings could be found in biopsies taken from normal areas of the forearm of the same patients. We conclude that the diabetic anhidrotic syndrome, a form of diabetic autonomic neuropathy, is due to a lesion of the sympathetic nerve supply to the skin. It is suggested that the Minor test or a skin biopsy should be performed in diabetic patients who are being considered for surgical sympathectomy.

Adrenergic Fibers↗
PubMed1982

Mutants of Saccharomyces cerevisiae cell division cycle defective in cytokinesis. Biosynthesis of the cell wall and morphology.

The four temperature-sensitive mutants of Saccharomyces cerevisiae in the cell division cycle defective in cytokinesis (cdc, 3, 10, 11 and 12), have been analyzed with respect to the biosynthesis of the cell wall polymers. After 3 hours of incubation at the non-permissive temperature (37 degrees C) these strains stop growing. The synthesis of glucan, mannan and chitin (wall polymers) level off in a similar time, but glucan, mannan and chitin synthases remained active for at least 4 hours. If the mutants are analyzed by transmission and scanning electron microscopy different pictures emerge. Two of the mutants cdc 10 and cdc 12, after 3 hours of incubation at 37 degrees C present apparently normal cytoplasms and cell wall surfaces with multiple elongated buds. The other two mutants, cdc 3 and cdc 11, present a completely disarranged cytoplasmic content and damage at the level of the plasma membrane is evident. These and other observations, suggest that between the execution points of cdc 3 (0.27) and cdc 10 (0.58), essential processes in the assembly of cell membrane occur.

Cell Division↗
PubMed1980

Yersinia enterocolitica Septicemia.

Human Yersinia enterocolitica septicemia is an uncommon condition. Four new cases are reported here and a review is made of 51 others taken from medical literature. Septicemia caused by this microorganism occurs more frequently in the young and in the elderly, and usually involves patients havig previous liver or blood disorders, diabetes mellitus, and other debilitating diseases. Clinically it is indistinguishable from sepsis caused by other organisms of Enterobacteriaceae, but it is important that the clinician bear its existence in mind, since Yersinia enterocolitica strains are usually resistant to beta-lactam antibiotics, whereas they are susceptible to the aminoglycosides and co-trimoxazole, among others. Susceptibilities in the blood isolates from our patients, and in another ten fecal isolates from eight other patients showed the previously described pattern. Our isolates, however, were all susceptible to the new cephalosporins, cefamandole and cefoxitin, and to the experimental ones, HR-756, T-1551, and Ly-127.935.

Adolescent↗
PubMed1979

[Treatment of malignant tumors of the conjunctiva with strontium-90 (author's transl)].

Although there are relatively few cases in our series of tumor of the conjunctiva, they represent most frequent histopathologic varieties for this localization. It is difficult to treat these patients in such a way as to cure the tumor while preserving intact the eye and vision. Surgery is recommended only in well differentiated cases that are diagnosed early. The excellent physical properties of strontium-90 make it particularly useful for this type of localization. High doses of radiation can be applied to the tumors with little danger to the deep and sensitive structures of the eye. With fractional doses we have been able to control conjunctival tumors of considerable size and thickness which would not normally have been considered tributary to this type of therapy.

Conjunctiva↗
PubMed1978

Inositol deficiency in yeast: metabolic, enzymatic and autoradiographic studies.

The addition of inositol to starved cells of Saccharomyces cerevisiae NCYC 86 resulted in an initiation of growth. Inositol was incorporated into phosphatidyl-inositol and after a lag period RNA was the first macromolecule with a rate of synthesis departing from the rate observed in deprived cells. Pulse chase experiments showed that inositol was first incorporated into phosphatidylinositol and later into more polar lipids. Finally it appeared to be excreted into the surrounding medium. When S. cerevisiae NCYC 86 was grown in suboptimal concentrations of inositol (0,5 microgram/ml), alterations in the level of some membrane-bound enzymatic activities were detected; these might reflect structural modifications of the cellular membranes due to a different composition of phospholipids. High-resolution autoradiography showed that inositol was probably first incorporated into internal membranes and later transferred to the plasma membrane. Analytical experiments carried out with inositol-deprived cells showed that inositol was released into the surrounding medium in that case. The unbalanced growth detected in S. cerevisiae NCYC 86 under inositol deprivation might be due to an abnormal functioning of the cell membranes as a consequence of the deficiency in inositol-containing phospholipids.

Autoradiography↗
PubMed1978

Inositol deficiency in Saccharomyces cerevisiae NCYC 86.

When Saccharomyces cerevisiae NCYC 86, an inositol dependent strain, is grown at suboptimal concentrations of inositol, the buds are apparently unable to separate from the parent cells. Thin sections of such cells show an irregularly thickened cell wall. These morphological features may be due to a continuation or increase in the production of glucan while the synthesis of DNA, RNA, phospholipids.and protein is greatly inhibited.

Cell Wall↗
PubMed1978

Biosynthesis of Saccharomyces cerevisiae glycoproteins: nature of some participating glycolipids.

A particulate membrane preparation from Saccharomyces cerevisiae catalyzed the incorporation of mannose from GDP-mannose into lipids that were extractable in chloroform-methanol. One lipid has been previously characterized as dolichyl phosphomannose. Another one was purified by chromatography on silicic acid, DEAE-cellulose and Sephadex LH-20 was found to be alkali unstable. The lipid moiety was shown to be dolichol and the glycosydic part contained mannose, glucose and glucosamine. Radioactive mannose was also incorporated at a slower rate into more polar compounds. They were soluble in chloroform-methanol-water and were seen to liberate neutral oligosaccharides after alkaline hydrolysis. Radioactive mannose was also incorporated into substances which behave chemically as glycoproteins since they were insoluble in organic solvents, water and trichloroactic acid. Pronase treatment of the trichloroacetic acid-insoluble material released water-soluble oligosaccharides. When the particulate preparation which had been extracted with chloroform-methanol at-20 C, was incubated with GDP-(U-14C)mannose, radioactivity was incorporated into glycolipids that were soluble in chloroform-methanol-water and into glycoproteins. This result suggests that at least part of the mannose was transferred to endogenous acceptors independent of dolichyl phosphomannose.

Cell-Free System↗
PubMed1977

Ultrasonic control of ocular dimensions and surgical indentations in retinal detachment.

Ultrasonography is a useful procedure to evaluate volumetric changes in the eye before and after retinal detachment surgery. We found myopic eyes to be variable in shape, most of them ovoidal, and some of them nearly spherical. Given a similar anteroposterior diameter, a spherical eye will have a larger volume than an ovoidal one, and a circling operation will produce a greater reduction than the same procedure in an ovoidal eye. Ultrasonography has been used also to measure the indentation produced by retinal surgery and to follow up its variations through the years.

Eye↗
PubMed1975

Electronic tonometry in the newborn.

Mackay-Marg electronic tonometry was performed without any kind of drugs in 604 eyes of newborn babies (up to 4 days of age). The first 100 cases were eliminated from the sample due to the significantly higher intraocular pressures obtained, attributed to small number of tonometries in each eye. The decision is fully discussed. The remaining cases (504 eyes) gave a mean of 12.41 mm Hg and a standard deviation of 2.58. The most important finding was the extreme and continuous variations found in newborn intraocular pressure; some hypotheses are discussed in this regard. The concept of 'basal intraocular pressure' is introduced to use the lowest intraocular pressure as a more homogenous comparative level than the ones previously used. Standardized anesthetic procedure is recommended for baby tonometry. While the possibilities of the Mackay-Marg electronic tonometer are recognized, the Goldmann tonometer (manual model) is found to be more reliable for clinical decisons in babies.

Adult↗